A 4,500-year-old Peruvian child, an 18th-century Hungarian family and a German nobleman dead since 1648 and still in his top boots: it's a motley cast that figures in the largest travelling collection of mummies ever assembled.

Mummies of the World, an exhibition that opened at the California Science Centre in Los Angeles, boasts 45 mummies and 95 artefacts from Asia, Oceania, South America, Europe and ancient Egypt, some dating as far back as 6,500 years.

The show started life after 20 human mummies thought to have been lost during the second world war were found at the Reiss-Engelhorn museums in Mannheim, Germany, in 2004. "The find was a big surprise," according to Dr Wilfried Rosendahl, the mummies' curator. "During construction work in one of our main buildings,, we discovered some mummies in a hidden corner. They were in an old box which was mislabelled 'ceramics'. It was full of bodies and mummified heads."

Rosendahl launched the German Mummy Project, an international and interdisciplinary research effort, to find out where they came from. "We thought we had one from Egypt, but we compared its DNA with a modern database and found it was actually from northeast Asia."

Researchers used radiocarbon dating and CT scanners to find out each mummy's geological age, and age at death. "We can get information about nutrition by looking at wearing of the teeth," Rosendahl says. You can tell if a mummy was vegetarian by analysing collagen isotopes in its hair. One child mummy's hair showed traces of nicotine.

Detailed analysis of textiles and bracelets worn by the mummies showed many were South American. One exciting discovery was of a mummy child. Under a special UV light, it could be seen that the whole body was covered in a natural resin. Previously, this embalming technique was only known in ancient Egyptian mummies. "We will show the world that mummies are not just from Egypt," Rosendahl adds triumphantly.